US 1951213 A
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March 13, 1934. P. SCHLUMBOHM COLOR FILTER MIRROR I Filed May 21, 1932 fie/Zecizlry lr/dca 1 1 1 u X U lNVENTORI 01 this kind have important than ?atented Mar. 13, 1934 UNITED STATES 1,951,213 COLOB-FILTER-MIREOB Peter Schlumbohm, Berlin, Germany Application May 21,
In Germany 1932, Serial No. 612,831 .lanuary 25, 1932 I 5 Claims. (cits-r) The combination of a mirror with a color filter is known and furthermore toilet mirrors preferably been made out of a silvered glass sheet, this glass sheet working as a color filter. Such a toilet mirror has been made for instance to show the photo effect of make-up and to be used as a make-up mirror for movie actors.
My present invention relates to a specific toilet mirror with a color filter adapted for the purpose of giving a daylight-effect reflection of a persons face in an artificially-lighted room. A woman who in the lamplight of her room is dressing and getting ready for taking a walk shall see under these light conditions in her room how she and especially her face will look in the daylight oi the street.
When attempting to make such a mirror with the information disclosed in the previous patent about color filter-mirrors no success could be obtained. A color-filter-mirror, the color-filter of which was composed following the rules of theoretical reckoning about spectral permeability, while apparently wholly correct, was found to be practically unusable. A mirror with such a filter made oi such a glass was found by testing persons to impression of oral whole impression and image.
By my new invention the mistakes are elimi-- nated which prevented success in the normal ways and experiments in constructing such a mirror. By my invention for the first time a toilet mirror for the specific purpose mentioned above has been materialized.
In the present embodiment'of my invention of which the attached drawing is illustrative,
Figure l is a perspective of the mirror and. related light and object;
Figure 2 is a substantially horizontal cross section through the mirror.
The invention is based on the thought that the psychological factors in this case are more the mathematical and physical factors or" the problem. I therefore decided to select the filter for such a toilet mirror from this point of view. A method was worked out which permitted control of these psychological factors and made possible the selection oi the right toilet mirrior from a large number oi trial filters and trial glasses;
Such a psychological method will bev explained in detail: A testing person was placed in such a way that the one side oi the face was the colors of the-face but the genthe intensity of the be unsatisfactory not only as to the v including violet, indigo,
lighted by daylight while the other side of the face was lighted by lamplight. Inorder to separate the two lights a screen was made which was placed vertically in the line of the nose, and which was out following the profile'of the testing person. Gpposite the eyes of the testing person, two mirrors were placed, one mirror on each side of the screen. The mirror on the daylight side of the face and screen was a normal white mirror without acolor filter; the mirror onthe other side of the face and screen, lighted up by an electric lamp, was a trial mirror with acolor filter.
Now: the color-filter mirror is correct and all-right if the testing person iudges the two difierent images in the two different mirrors to be equal. It is practical to make the tests with a daylight of a medium intensity.
The new mirror 12, having the reflecting back surface 13, has a coloring matter giving the glass a bluish tint. It can therefore be characterized by the efiects that the image is of the face of the person 10 which is artificially lighted by the lamp 145 is equal to the image of the same persons face in a normal white mirror if 3 in this latter case the persons face is illuminated by daylight.
Daylight is characterized as having preconderance of rays of the shorter wave lengths including violet, indigo, blue and a relatively smaller percentage of rays of the longer wave lengths including red. Artificial light as reierred to is characterized as having a great predominance of rays of longer wave length including yellow, orange, red, and a very small percentage of rays of the shorter wave lengths blue.
Of the several methods for making the daylight filter glass I prefer the addition 01 a miri ture of copperoxyd and cobaltcxyd to the glass.
For the making of my product two factors in the formula are of importance: the relation of the copperoxyd to the cobaltoxyd and the concentration of the mixture of the two substances in the glass.
I consider a proportion of copperoxyd: cobalt oxyd=lzl to be the optimum proportion for the said purpose.
As far as the concentration oi the color in its proportion to the glass is concerned, it is a matter of fact that the percent 0' concentration by weight relates to a particular thickness of the glass, since the quality ofthe filter changeswith the thickness of the glass. The best concentration for the glass of the mirror is for a thicknessof 3 l have also given a formule for s can be usesi for the mirror.
Formula foe o gloss of ooze coo :IIII, o,
Having now described my invention and having oisclosed the method new to incite and now test soon a new mirror, I claim: 7
What i olefin is:
l. A toilet mirror of the class described, comrising gloss hevinge, reflecting material on no side thereof, said. glass having a, coloring matter therein rendering the glass capable cocci-one a. portion of light waves reflected from an object illuminated by artificial light which contains e greater proportion of longer waves to ves then daylight, the quantity and -l said coloring matter being snficient absorb sucli e portion of seiti longer waves as ,2 cause the mirror to reflect image of the object in light having approximately the same proportion of long waves to short waves as daylight, whereby the image will appear the some as then i the object were illuminated by daylight the image were seen in e normal 2. A. toilet mirror of class describeo, comprising a glass having" ere'flecting' materiel on one side thereof, said gless listing a coloring matter therein rendering the glass capable of absorbing e portion of light veeves reflected from an object illuminate-i by artificial light which contains a greater pronortion or" longer Waves to short Waves than daylight, the quantity end quality of coloring matter being sufiiicient with time following eoncen neticn, glass which,
' iizen the theoretical requirement bsorb seen a, portion of said longer Waves will cause tile mirror to reflect an image of the ooject lielit having approximately the same proportion of long waves to short waves as daylight, whereby the image will appear the some as though the object were illuminated by light and the image were seen in 2. normal ess, saicl amount of coloring matter being less the spectral permeability of the glass.
3. A niri'or as claimed. in claim 1, the glass seid'rnirror having epproximetelv the formula SiQi, 7e92,; CeO, 11%; E 0, 4% and N220, 11%, said glass having added thereto a, mixture of to the weight of the glass.
l. A mirror as claimed in claim 1, the gloss of sell mirror having substantially the formula, 74%, S102; 11% Ca(); 2%, K and 11%,Nez0, said glass having a coloring substance embodied therein consisting of approximately .625% by weight of cobalt oxide end .025% by weight of copper oxide, said glass having a thickness of approximately 3 min.
5. A toilet mirror of the class described, comnrising a glass having a reflecting material on an object illuminated by artificial light which contains a, greater to short waves than quality of said coloring matter being sufficient to absorb such a portion of said longer waves as will cause the mirror to reflect an image of the object in light having a balance of short and long waves adapted PETER SCHLUIEBOEEE.